- Ningbo Zhongli bolts manufacturing Co., Ltd. +86-574-86587617
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Industry-leading high-strength fasteners engineered to meet global construction standards — from steel structures to heavy civil engineering projects.
DIN6914 HV EN14399-3 Structural Hexagon Bolts for Steel Frame Construction
Hexagon Socket Head Cap Screws DIN912 ISO4762 for Industrial Construction
Heavy Hexagon-Head Bolts ASTM A325 for Bridge & Building Construction
Stud Bolt DIN975 Threaded Metal Studs & Rods B7 for Construction Projects
Ningbo Zhongli Bolts Manufacturing Co., Ltd. founded in 2003, is a professional manufacturer of high-strength fasteners in different specifications for various models, which is covering an area of about 10,000 square meters, registered capital of 1,500,000 RMB, with the total annual productivity of 8,000 tons per year.
The company has set up several sales branches in different provinces in China. Meanwhile, the company's products are exported to Europe, USA, Middle East, Africa, Southeast Asia and other regions. The company has strong technical ability, complete testing equipments and a variety of fully automatic multi-station cold and hot heading machines, so as to provide you with reliable and high quality products.
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The global structural bolt market is experiencing robust growth driven by accelerating urbanization, infrastructure investment, and the expansion of steel-intensive construction methods worldwide.
The global fastener market is projected to surpass USD 130 billion by 2028, with structural bolts for construction accounting for a significant and growing share. Demand is surging across Asia-Pacific, North America, and Europe as governments commit to large-scale infrastructure renewal programs, green building initiatives, and high-speed rail networks.
Structural bolts are the unsung heroes of modern construction. From skyscrapers and suspension bridges to industrial warehouses and wind turbine towers, high-strength structural fasteners provide the critical connections that hold steel frameworks together under dynamic loads, seismic activity, and environmental stress. Unlike ordinary bolts, structural bolts — such as ASTM A325, ASTM A490, and EN14399 grades — are engineered to precise mechanical specifications, ensuring predictable clamping force, fatigue resistance, and long-term durability.
The construction industry's shift toward prefabricated and modular steel structures has significantly increased demand for standardized, high-quality structural bolts. Contractors and structural engineers now demand fasteners that not only meet dimensional tolerances but also comply with international certifications such as ISO9001, CE (EN15048, EN14399), and ASTM standards — all of which Ningbo Zhongli Bolts Manufacturing Co., Ltd. proudly holds.
Key macro and technological trends reshaping how structural bolts are specified, sourced, and applied in construction projects globally.
Rapid urbanization across Southeast Asia, Africa, and the Middle East is fueling unprecedented demand for steel structures. High-rise commercial buildings, metro systems, and airports require millions of certified structural bolts per project. Governments' infrastructure stimulus packages — particularly post-pandemic recovery programs — have created sustained demand spikes for ASTM A325, A490, and DIN6914 grade fasteners.
The push for LEED-certified and carbon-neutral buildings is driving adoption of hot-dip galvanized and environmentally compliant fasteners. Zinc-plated and HDG structural bolts extend service life, reduce maintenance cycles, and lower the lifecycle carbon footprint of steel structures — aligning with ESG commitments that are now standard requirements for major construction procurement.
Off-site prefabrication is transforming construction timelines. Modular steel buildings demand fasteners with extremely tight dimensional tolerances and consistent mechanical properties to ensure rapid, error-free on-site assembly. This trend is accelerating standardization around DIN931, DIN933, ISO4014, and ISO4017 hex bolts in grades 8.8, 10.9, and 12.9.
Wind turbine towers, solar mounting structures, and hydroelectric facilities represent fast-growing end markets for structural bolts. Wind turbine flanges, for instance, require large-diameter high-strength bolts (M30–M48) with exceptional fatigue resistance. Zhongli's capacity to supply diameters from M10 to M48 positions it perfectly for this booming sector.
Innovation in bolt coatings — including geomet, dacromet, PTFE, and hot-dip galvanizing — is extending service life in corrosive marine and industrial environments. Manufacturers who invest in advanced surface treatment capabilities gain a decisive competitive edge as construction projects in coastal and chemical-process environments become more prevalent.
Construction companies are increasingly leveraging digital platforms for bolt procurement, demanding full material traceability, mill certificates, and third-party inspection reports. Suppliers with robust quality management systems — like Zhongli's ISO9001-certified operations — are winning long-term contracts as buyers prioritize verified quality over price alone.
Where structural bolts make the critical difference — from landmark skyscrapers to offshore platforms.
Multi-story commercial and residential towers rely on high-strength hex bolts (ASTM A325, A490, EN14399) for moment-resisting and shear connections. These joints must withstand wind loads, seismic forces, and long-term fatigue. Proper bolt pretensioning — achieved through turn-of-nut or direct tension indicator methods — is critical for structural integrity and building code compliance.
Bridge girder splices, truss connections, and bearing plate assemblies demand bolts with exceptional tensile strength and fatigue resistance. ASTM A325 and A490 heavy hex bolts are the standard specification for North American bridge projects, while EN14399 HV bolts are preferred in European infrastructure. Hot-dip galvanized finishes provide the corrosion protection essential for bridges exposed to road salt and moisture.
Large-span portal frame warehouses, logistics centers, and manufacturing facilities use thousands of structural bolts in column base plates, rafter connections, and crane runway beams. The combination of DIN6914 structural hex bolts with DIN6915 heavy nuts and DIN6916 washers provides the high-friction slip-resistant connections required by industrial loading standards.
Each wind turbine tower section requires hundreds of large-diameter flange bolts (M30–M48, grade 10.9) to connect tower segments and anchor the structure to its foundation. These bolts operate under cyclic loading and must maintain precise preload over a 25-year design life. Zhongli's capacity to produce bolts up to M48 with no length limitation makes it an ideal supply partner for wind energy projects.
High-speed rail viaducts, station canopies, and rail bridge structures require certified structural bolts with full material traceability. A193 B7 stud bolts and threaded rods are widely used in rail infrastructure for anchoring equipment, securing expansion joints, and connecting precast concrete elements to steel frameworks. Compliance with international rail authority specifications is non-negotiable.
Offshore oil platforms, marine terminals, and coastal infrastructure demand bolts with superior corrosion resistance. Hot-dip galvanized structural bolts with zinc coating thicknesses per ISO1461 provide reliable protection in salt-spray environments. For the most aggressive conditions, duplex stainless or special alloy fasteners are specified — Zhongli's customization capability allows non-standard specifications to be manufactured to order.
Our ZYL brand fasteners cover the full spectrum of structural and industrial bolt specifications. Main products include structural hex bolts ASTM A325 type 1, A490, hex head bolts DIN931, DIN933, EN14399, DIN6914, ISO4014, ISO4017 Gr8.8 Gr10.9 Gr12.9, ANSI B18.2.1 UNC and UNF Gr5, Gr8, fine pitch hex bolts DIN960, DIN961 Gr8.8 Gr10.9 Gr12.9, hex socket cap screws DIN912, ISO4762 Gr8.8 Gr10.9 Gr12.9 with surface Black, Zinc plated, Hot dip galvanized. Diameters from M10 to M48, length no limited.
Hex Flange bolts DIN6921 Gr8.8 Gr10.9 with serration, thread rod A193 B7 long sizes and short sizes with 2H nuts, stud bolts. We also supply hex nuts DIN934, DIN6915, plain washers DIN125, DIN126, DIN6916, spring washers DIN127 with Black, Zinc plated and Hot dip galvanized surface. Our physical and mechanical test results can reach to ISO898-1 for bolts and ISO898-2 for nuts.
Through scientific management, Ningbo Zhongli Bolts Manufacturing Co., Ltd. obtained ISO9001 certificate of Quality Management System. Quality is the most important for us. We have strict production and inspection equipments to support this point. We hope to establish business relationship with all over the world, and our business can bring in mutual benefits for both parties.
Every structural bolt manufactured at Zhongli undergoes a rigorous multi-stage production process, ensuring consistent quality from raw material to finished product.
State-of-the-art manufacturing facilities with fully automatic multi-station cold and hot heading machines ensuring precision and consistency.
Why leading construction companies and steel fabricators worldwide choose Zhongli as their trusted structural bolt supplier.
A Professional Sales and Technical Team with More Than 20 Years History.
We Have Our Own Testing Equipment and Laboratory, Our Products Have Initial Inspection, Patrol Inspection, And Final Inspection.
Our Factory Has Its Own Cold Forged, Hot Forged, And Heat Treatment Equipment.
Standard Fasteners in Stock, Non-standard Fasteners Can Be Customized.
We Have Passed ISO 9001, EN 15048, EN 14399, AD2000 and CE Certificates.
We hope to establish business relationships with partners all over the world, and our business can bring mutual benefits for both parties.
Every batch of structural bolts undergoes rigorous multi-stage quality inspection before shipment. Our dedicated laboratory and testing equipment ensure that all products meet or exceed international standards for dimensional accuracy, mechanical strength, and surface finish.
I N T R O D U C T I O N
Founded in 2003, Ningbo Zhongli Bolts Manufacturing Co., Ltd. is a professional manufacturer of high-strength fasteners in different specifications for various models, which covers an area of about 10,000 square meters, registered capital of 1,500,000 RMB, with the total annual productivity of 8,000 tons per year.
The company has set up several sales branches in different provinces in China, with products exported to Europe, USA, Middle East, Africa, Southeast Asia and other regions. Through scientific management, the company obtained ISO9001 certificate of Quality Management System.
Read MoreEN 15048 CE Certification · EN14399 CE Certification · ISO9001 Certificate
Grasp first-hand information — what our global construction clients say about our structural bolt quality and service.
Explore our complete range of high-strength fasteners — engineered for every construction challenge, certified for global markets.
ISO4017 Hexagon Head Bolt Fine Coarse Thread UNC & UNF for Construction
Zinc Plated Hex Bolt Hexagon Head Fine Coarse Thread UNC & UNF for Steel Structure
L7 Stud Bolt Threaded Metal Studs and Rods B7 for Industrial Construction
M30 DIN6914 Structural Hexagon Bolts for Heavy Steel Construction Projects
ASTM A307 DIN6914 EN14399-3 Structural Hexagon Bolts for Construction
DIN912 ISO4762 Hexagon Socket Head Cap Screws for Precision Construction
ASTM A325 Heavy Hexagon-Head Bolts Zinc Plated for Bridge & Building Construction
DIN975 Stud Bolt Threaded Metal Studs and Rods B7 for Construction Applications
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